### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

If I pass a completion request to a cohere model with 'n' supplied, it fails:

```python import litellm import os

os.environ["COHERE_API_KEY"] = "..." model_id = "cohere/command-r7b-12-2024" messages = [{"role": "user", "content": "In one word, what color is the sky?"}]

response = litellm.completion(model=model_id, messages=messages, n=1) ```

Expected successful completion. Actually got: ```python litellm.exceptions.APIConnectionError: litellm.APIConnectionError: Cohere_chatException - {"id":"3d71291b-8a91-44e9-8431-d1337b90a07b","message":"unknown field: parameter 'num_generations' is not a valid field. For proper usage, please refer to https://docs.cohere.com/reference/chat"} ```

Likely stemming from [this line](https://github.com/BerriAI/litellm/blob/c1b6c4062ef5372c1e5e0027c721a942d2bb66cb/litellm/llms/cohere/chat/transformation.py#L167)

### Steps to Reproduce

1. install litellm==1.93.0 2. Use above code example, include `n=<number>` in the args

### Relevant log output

```shell

```

### What part of LiteLLM is this about?

SDK (li…